This study investigated the teachers’ use of recommended assessment methods in implementing the Competence Based Curriculum (CBC) in public secondary schools in Arumeru District of Tanzania. More specifically, the study sought to determine teacher training in and utilization of the recommended assessment methods implementing the CBC. Adopting the cross-sectional survey research design, the study targeted 35 co-educational public secondary schools in Meru Council of Arumeru District, Tanzania with a population of 1193 teachers. The study sample comprised 111 teachers drawn from nine secondary schools, which were sampled using stratified sampling to ensure proportional representation of rural and urban schools. Data were collected using a semi-structured questionnaire. The findings revealed that a majority of the secondary school teachers were not trained in the recommended assessment methods for implementing CBC, more so in the use of rating scales and rubrics, checklists, portfolios, practical task, and analysis of texts. The methods that were primarily used by teachers to assess student learning were oral examination, written tests, analysis of texts, and essays. On the contrary, portfolios, rating scales, and rubrics, checklists, projects, and practical task methods were rarely used in assessing student learning. The study, therefore, recommends that the Ministry of Education, Science and Technology should ensure that all secondary school teachers are trained in the use of the recommended assessment methods if the implementation of CBC were to be successful. In addition, the Ministry of Education, Science and Technology should closely and continuously monitor utilization of the different recommended assessment methods for effective assessment of learning outcomes in secondary schools.